Egypt’s Muslim Brotherhood says another of its members has been killed by security forces two weeks after the man went missing, the movement has told Al Jazeera.

The group on Friday said Egyptian soldiers kidnapped two men, a businessman Tarek Khalil, who was in charge of the Brotherhood’s Development Committee, and another man, Mohamed Saad Alioua, on June 17.

Muslim Brotherhood members said Egyptian authorities asked Khalil’s family to collect his body from a mortuary on Friday. Family members said Khalil’s body showed marks of torture.

The group did not have information on what has happened to Alioua.

Calls for ‘revolt’

On Thursday the Brotherhood warned of “serious repercussions” and called on its supporters to “rise in revolt” after Egyptian police killed 13 leading members of the group.

Egyptian police raided an apartment in the Cairo suburb of 6th of October on Wednesday and killed the men, including a former member of parliament, Nasser al-Hafy, security sources and a member of the outlawed group said.

The Brotherhood members were reportedly meeting to discuss sponsoring the families of detainees when the police stormed the building. The victims’ families said the men were unarmed and had been taken into custody earlier in the day but were released after giving fingerprints.

Egypt’s interior ministry, however, said the men were fugitive leaders who were plotting attacks – something the group denies – and said the group included two men who had previously been sentenced to death.

In a statement, the ministry said that investigators found weapons, 43,000 Egyptian pounds ($5,300), documents and memory cards and that the group was plotting attacks on the army, police, judiciary, and media.

Pro-Muslim Brotherhood Mekameleen TV said the leaders were detained inside a home and “killed in cold blood without any investigation or charges”.

In a statement following the deaths, the group described the killings as “a significant development with serious repercussions” and said it held “the criminal [Egyptian President] Abdel Fattah el-Sisi and his gang fully responsible for these crimes and their consequences”.

“Rise in revolt to defend your homeland, your lives and your children,” the statement said, adding: “This murderer is now executing the largest and most horrid massacre against this homeland. Oust the heinous murderer. Destroy the castles of injustice and tyranny. Reclaim Egypt once again.”

The group said the incident “pushes the situation onto a very dangerous curve and makes the entire scene highly volatile”.